Worldwide more than 50 million tons of fillers for different application areas, such as paper, plastics, rubber, paints and adhesives, are consumed annually. Fillers are substances that are used predominantly to cheapen end products. However, there are special fillers that are also able to enhance mechanical or optical properties of the end products and these are called functional fillers or functional additives.
Thermoplastics and thermosets are traditionally the most important application market, accounting for 26% of the total inorganic filler market demand. The presence and/or arrangement of the filler particles within the matrix can even affect intrinsic properties of the matrix, e.g., crystallinity (nucleation) and glass transition temperature (hindered conformal molecular motion). However, in most cases, formulators are seeking improvement in mechanical and thermal properties.